Thermostatic switch



J. P. STEFN THERMOSTATIC SWITCH WN En L Filed. Ooi.

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may 9 m5@ J. F. STEFAN THERMOSTATIC SWITCH Filed Oct. l5, 1947 2 sheets-Sheet 2 Inverno? Patented May 9, 1950 UNITED lSTATES PATENT OFFICE THERMOSTATIG SWITCH Joseph P. Stefan, Park, Kans.

`A, pplicationOctober 15, 1947, vSerial No. 779,852

A1 Claim.

. This invention relates generally .to poultry broeders, and `more particularly to va temperature alarm and correction SYStem, adapted to provide a signal when -the temperature rises or falls beyond predetermined vhigh and low limits, and 1to energize aheating unit when the temperature falls below the low limit, the `device including a specially designed snap switch construction embodied in the electrical `switches used in the system.

A primary object of this invention is, therefore, to provide signal and control means whereby the operator of poultry brooder .equipment may better control the temperature of the brooder equipment, it being understood that this invention is primarily `designed for use as an auxiliary unit for use with regular thermostatic control and heating equipment for the brooder, although this equipment slightly modified may, if desired, bc used as a primary or sole heat control unit.

Another salient object ,of this invention is to provide means of this character with novel switch devices of very .simple form and designed to provide a type ,of snap action particularly .acceptable for use with this system.

Still another more specic object is .to provide a switch construction in which the closing and opening .of ,the switch is characterized by a strongsnap action and in which ,the Switch .contacts will remainclosed pending a wide variation in temperature after once being closed.

And .a last object to be vspecifically mentioned is to provide .a device .of ,this character which is relatively inexpensive and practicable ,to manu.- facture, extremely simple to install and .convenient to use, and which will give generally1 eflicient and .durable service.

With these objects Vdefinitely in View, together with other objects which will appear as this description proceeds, this invention resides certain novel features oi construction, combination andl arrangement of parts and portions as will .be vhereinafter described in detail in the specication, particularly pointed out in the appended claim, and illustrated in .the `accompanying drawings which form a material part of this application and in which:

Figure 1 is a somewhat diagrammatic view of the diierent units in this invention operativelf,v connected together.

Figure v2 is an enlarged horizontal sectional view through the casing for Ythe specially ,designed switch construction, showing the kmain lportions 4of the switch construction in plan, the

View being taken on the line 2-2 in Figure l;

Figure 3is a vertical longitudinal sectional view, taken on the line ,3- 3 in Figure 2:

Figure 4 is an elevational View of a single switch unit, such as that represented in vertical section at the right hand side of Figure 3;

(Cl. '20G- 140) jFigure 5 is a similar view of the double switch construction; and

Figure 6 is a diagrammatic view showing the electrical connections.

Similar characters of reference designate similar or identical parts and portions throughout the specication and throughout the several views of the drawings.

TSteier-ring now to the drawings lin detail, it should rst be understood that this invention is primarily adapted for use with an environment including a brooder or brooder house having a main thermostatically controlled heating unit, the subject matter of this invention being primarily a signal system to indicate the improper functioning of the `main heating and Ventilating Y system, and to provide an auxiliary heating unit system which will be automatically put into operation `at the same time as the signal of too low a temperature is given.

The system includes an auxiliary heater I0, an audible signal unit I2, `a vthermostat unit i4 .and control switches I6 and I8 of double and single character, respectively, together with a complement of electrical conduits, an alarm switch 2,!) and certain other minor features of construction.

The casing 22 is represented vas being rectangular in form and is provided with louver openings 24, and simple openings 26, so that the interior of the casing is at all times approximately the same temperature as the brooder or brooder house in which the casing is situated. A pair of bosses 2 8 and 3G vare provided at theends of the casing. The boss 28 is interiorly threaded to directly receive the adjusting screw 32 and the boss 30 comprises a bearing to receive ya projecting boss 44 on a rectangular yoke 42, and an adjusting screw 34 is threaded through the boss 44, these adjusting screws being locked at any predetermined adjustment by wing nuts 36. T he thermostat unit I4 is connected to the inner end of the screw 32, by means of a rotating bearing terminal 33, or by any other suitable means. to allow the longitudinal vadjustment of the screw 32 for shifting of the thermostat I4 without the rotation of the thermostat. The other side of the thermostat may be rigidly secured tothe projecting arm 40 of the rectangular yoke 42. The yoke 42 is shifted by said thermostat vand is designed to Operate the lswitches I6 and I8.

The switch I6 is essentially a duplication of the switch I; 8 which will now be described. This switch Yincludes a housing 50 which is mounted on brackets 52 and the housing is provided with a rigid diaphragm 54. The rlxed contact 56 ofthe switch is secured to this diaphragm 54 and the moving contact 518 of the switch is carried by a lever arm 50 which is pivoted as at `62 on this same diaphragm. The lever arm 60 extends, as

at 64, beyond the pivot 52 and carries a resilient contact bar 68. The resilient contact bar 6E is returned to the central portion of the housing 50 and isadapted to bepactuatedby a push pin 8-8, this push pin being slidably mounted in the central portion of the wall of the housing '58, and positioned for contact by the portion L82 of the yoke 42 corresponding functionally with the screw 34, it being understood that this yoke 82 encircles the switches |18 Aand i8. The resilient contact bar 6B is extended beyond itsconnection with the lever portion 68 and the extending arm overheating of the poultry will be signalled by the actuation of the alarm unit I2 which will ordinarily be placed in the home of the operator or in sonne other-suitable location and it will be obvious that theswitch 28may be used to open this circuit to discontinue the ringing of the bell fi2 after the signal has been given. Underheating 10 must be of magnetic material for coaction Y with a permanent magnet 72 secured to the casing 50 adjacent the end of the said extending portion 18. Magnetic "attraction between the portion 'I8 and the magnet 'I2 biases the moving contact 58 toward the fixed contact 58.

It will be apparent from the foregoing, that actuation of the yoke 42 will move the push pin 618 and will force the arm 85 as to the left in Figure 3, to open the switch I 8 when the yoke is moved to the direction as to the left in Figure 3. A flexible electrical connection 14 and a lead 'le complete the essential features of this switch construction. The other switch i8, which is represented in Figure 5 will be seen to be a mere duplication of the switch i8, inasmuch as the switch i6 is comprised of two similar units with the spring bars B8 joined by a lever or cross brace 18, the cross brace 18 being actuated by the pin 88 which, in turn, is moved in one direction by the portion 82 of the yoke 42. A single large permanent magnet 84 may be used in place of two smaller magnets 12. For purposes of reference, the two parts of this double switch will be differentiated by the numerals 86 and 88, in Figure 6.

, Referring now to Figure 6, it will be seen that the switches 86 and 88 are each connected to one side of the power leads 98, and that these power leads are controlled by a master switch 92. It will also be noted that the same lead as is connected directly to the switches 86 and 88 is also connected by means of the connection 9@ to the single switch i8. The Figure 6 represents a condition in which the upper limit of temperature has beenreached and the yoke 42 has been moved as to the right in this ligure closing the switch |18 and leading power through this switch and through the leads 9G, 98 and the switch 20 to the step-down transformer |08 and the return lead |82. The step-down transformei- |89 supplies power at proper voltage to the electric bell l2, or othersuitable signal. Movement of the yoke 42 in the opposite direction, that is, as t0 the left in Figure 6 will close the switches 88 and l88 leading power through the leads |06 and 198 to the leads H8 and H2 and energizing the heater I8, while simultaneously energizing the electric bell I2. The operation of this invention has already been described in connection with the description of the mechanical details of construction, and it'should now be evident that this invention will accomplishl the objects sought to be achieved thereby. In recapitulatlon, heating of the thermostat unit i4 will cause the yoke to be moved in one direction while chilling of the brooder or brooder house will cause the yoke to be moved in the opposite direction. Normal temperature within the brooder or brooder house will allow all the switches to be in open position.

of the brooder or brooder house will provide a similar signal by closing the switch y86 and will also cause the energization of the heater I8 by closing the switch 88. Since this device is ordinarily used in connection with the rearing of very young chicks, too low a temperature in the brooder or brooder house will quickly cause a high rate of mortality amongst thesechicks, and the lauxiliary heater I8 has been found to ameliorate the damage caused by failure of the main heating system, when the operator is un| able to give absolutely immediate attention to the problem of restoring proper heating facilities. The special construction of the switches has been developed in order that each switch, once closed, will remain closed under` the influence of the magnets i2 or 84, even though the yoke 42 may be moved in either direction slightly as by variations of temperature conditions and actual repair or proper adjustment of the main heating system has not been accomplished, the operator being therefore warned of the failure of the heating system even though this failure occurred during his absence and even if this failure is not apparent upon his return, as when weather conditions have changed in the meantime in a manner to make such failure not otherwise easily detectible.

Many minor variations may be made in the structure as disclosed in this application y and this invention should be limited only by a proper interpretation of the terminology of the appended claim.

Having described the invention, what is claimed as new 1s:

A circuit closer for a temperature alarm and correction system comprising a casing, a yoke slidably mounted in said casing, a thermostat wafer unit adjustably mounted in the casing and operatively connected to said yoke, said yoke having a switch operating member Xed on one end of the yoke and an adjustable switch operating member onvthe opposite end of the yoke, switches mounted on said casing andr having contacts in-` dividually operated by said switch operating members, whereby the adjustment of the wafer unit adjusts the yoke with reference toV both switches and adjustment of said adjustable switch operating member affects the operation of one switch.

` JOSEPH P. STEFAN.

REFERENCES CITED The following references are of record in the le of this patent:

- UNITED STATES PATENTS Ray Dec. 14, 1943 

